The present invention relates to novel thermoplastic elastomers which have improved thermal aging performance. More specifically, this invention relates to blends of copolyetherimide esters and polyamides ("nylons") which exhibit increased thermal aging performance when compared to the copolyetherimide ester resin alone.
Copolyetherimide esters are well known and have been described in a number of patents and publications such as U.S. Pat. Nos. 4,556,705 and 4,659,765 both assigned to the General Electric Company. These copolyetherimide esters are based on low molecular weight diols, dicarboxylic acids and polyoxyalkylene diimide diesters, and exhibit a variety of advantageous properties. These compositions are commercially available from the General Electric Company under the Lomod.RTM. tradename.
Copolyetherimide ester thermoplastics are suitable for the internal components of microwave ovens, electrical and electronic products, automotive, appliance and aerospace/transportation applications especially where temperatures above 120.degree. C. and up to about 180.degree. C. are often encountered. In general, thermoplastic elastomers exposed to such high temperatures over periods of time tend to undergo oxidative degradation, whereupon they no longer provide optimal properties. U.S. Pat. No. 3,896,078 discloses a blend of a copolyether ester with polyamides reportedly having greatly enhanced resistance toward oxidative degradation, in particular degradation at temperatures of about 120.degree. C. to 200.degree. C.
Although there are thermoplastic elastomers that can withstand high temperatures, there is still a need to improve the thermal aging performance in copolyetherimide ester compositions.